Sept 23, 2020 COVID-19 Risks and precautions for the performing arts

National Collaborating Centre for Environmental Health 1

COVID-19 Risks and precautions for the performing

arts Prepared by

Juliette O’Keeffe

Introduction

The COVID-19 pandemic has caused major changes to how musicians and performers practise and

rehearse and has brought many live performances to a halt. Restrictions have been put in place to

reduce transmission risks for those who work or volunteer in the sector, and for audiences

attending performances. This document synthesizes available evidence to date on transmission

risks of SARS-CoV-2, the virus responsible for COVID-19, associated with performing arts activities.

The document provides an overview of notable outbreaks that have occurred in performing arts

settings and presents an overview of mitigation measures to reduce transmission risks from live

theatre, music and dance. This is a companion document to COVID-19 Risks and Precautions for

Choirs. The literature search method and search terms are provided in Appendix 1.

COVID-19 outbreaks and the performing arts

Public health measures implemented at the beginning of the COVID-19 pandemic restricted large

gatherings, which included performances with a live audience in theatres, auditoriums, and other

venues. Gathering in groups was identified as high-risk for SARS-CoV-2 transmission, and limits on

the number of people gathering was an essential public health tool for reducing community

transmission. In many jurisdictions, public health guidance expanded to include restrictions on

activities where there was likely to be group singing, cheering, or other types of loud vocalization

following notable outbreaks associated with singing in groups in Washington State,1 Amsterdam,2

Berlin, and France.3 These events reported high COVID-19 attack ratesa among attendees of choir

rehearsals and performances. Other COVID-19 clusters and outbreaks associated with performing

arts activities are presented in Table 1. Several of these share characteristics that can help to

identify common risk factors. An analysis of COVID-19 clusters in Japan between January 15 and

April 4, 2020, found that 11% of 61 clusters in the country were linked to music-related events (live

concert, choral group rehearsal, karaoke party).4 Common features included enclosed and crowded

a The proportion of people that are infected following an exposure event

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indoor spaces with close-contact occurring between patrons.5 Elsewhere, other outbreaks share

common characteristics of crowding or gathering in large groups, enclosed spaces or poor

ventilation, long duration of contact, person-to-person interactions such as greetings and social

interactions, sharing of food, drinks or equipment, and shared transport. In addition, many of those

affected participated in activities such as singing, shouting, or heavy breathing due to vigorous

physical activity such as dance.

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Table 1 Media and literature reports of COVID-19 clusters and outbreaks associated with performing arts activities including singing, dance, theatre and bands

Location Date (2020)

Type of performing art

Settings/ Type of event

Outcome of outbreak Ref

Amsterdam, Netherlands

Feb 28 –

Mar 8

Choir Orchestra

Rehearsal Performance

102 of 130 choir participants fell ill with COVID-19 following multiple rehearsals and a performance. One member and three close contacts died.

2

France Feb 28 –Mar 12

Choir Rehearsal Multiple choirs with outbreaks resulting in hospitalizations and deaths. 3

Berlin, Germany

Mar 9 Choir Rehearsal 60 cases from 80 choir participants following one practice. 3

Skagit Valley, USA

Mar 10 Choir Rehearsal 53 cases from 61 choir participants following one practice, resulting in two deaths. 1,6

Berrien Springs, USA

Mar 8 Solo vocal performance

Performance Backstage interaction

A singer tested positive for COVID-19 nine days after the event. Two attendees that had a backstage experience with the singer also tested positive.

7

Otaru, Japan Jun 2020 Singing Karaoke Three clusters associated with karaoke establishments resulting in more than 30 cases, including customers and close contacts.

8

Quebec City, Canada

Aug 2020 Singing Karaoke 63 cases plus 18 secondary cases including children linked to two index cases attended a karaoke night at a bar with a 100-person capacity limit while awaiting COVID-19 test results.

9

Cheonan, South Korea

Feb 15 –

Mar 13

Dance Group fitness and/or dance instruction at multiple facilities

Instructors who were asymptomatic or mildly symptomatic held classes resulting in subsequent infection of > 100 students, family members and other contacts across multiple facilities. These events involved intense physical exercise in densely populated facilities. Classes with fewer participants and less intense activity (e.g., yoga) had no cases.

10,11

Detroit, USA Apr 2020 Dance Social dance events

Several cases and deaths due to COVID-19 were reported among attendees of ballroom dance activities, but no event or venue was confirmed as an exposure site.

12

Moscow, Russia

Apr 2020 Dance Rehearsals 34 cases identified following COVID-19 screening of the Bolshoi Ballet company two days prior to a performance, despite none being symptomatic.

13,14

Montreal, Canada

Jul 31 –

Aug 15

Dance Instruction Three persons attending Latin dance events later tested positive for COVID-19, and exposures may have occurred in both indoor and outdoor venues.

15

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Location Date (2020)

Type of performing art

Settings/ Type of event

Outcome of outbreak Ref

Vancouver, Canada

Aug 2 – 11

Dance Dance community party, Instruction

A dance instructor tested positive for COVID-19 on Aug 11, following a dance community party on August 2. A student returning from China also tested positive and may have been asymptomatic while attending the dance centre.

16

St. Petersburg, Russia

Aug 13 Dance Rehearsals Over 50 cases in the Mariinsky Ballet company, including many dancers, following the return to rehearsals and performances. Some hospitalizations were reported.

13

Japan Jan 15 –

Apr 4

Various large music venues

Performances 11% of 61 clusters in Japan were associated with music-related events including karaoke singing, live concerts, loud environments, in crowded and poorly ventilated venues.

4,5

Osaka, Japan Feb 15 –

25

Live music Eight “Live House” small concerts linked to four music clubs of 50-100 capacity resulting in 100 cases among patrons and their contacts.

17,18

Tokyo, Japan Jun 30 –

Jul 5

Theatre Performance Over 30 cases including staff, cast members and theatregoers, with up to 800 exposures following five days of theatre performances in a small 186 seat theatre operating at 50% capacity.

19

Kaysville Utah, USA

Jul 2020 Theatre Rehearsals Six cases identified among case and crew during rehearsals for a small theatre production, halting production.

20

Franklin County, Tenn, USA

Sept 2020 Band Rehearsals Several cases among high school band members, bringing a suspension of rehearsals and performances. Details on the number of individuals affected, or any outbreak investigation were unavailable.

21

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Overview of transmission pathways for SARS-CoV-2

Coronavirus disease 2019 (COVID-19) is an illness caused by the severe acute respiratory syndrome

coronavirus 2 (SARS-CoV-2). Since the beginning of the pandemic, the scientific community has

been gathering evidence from epidemiological investigations and experimental work to

understand the drivers for infection. These include the transmission pathways, the dose needed to

cause infection, and the susceptibility of the exposed persons to infection. This section provides an

overview of the transmission pathways for SARS-CoV-2.

Respiratory droplets and aerosols

Currently, the primary mode of human-to-human transmission for SARS-CoV-2 is considered to be

via prolonged close contact with an infected person and their respiratory emissions.22 Respiratory

emissions can range in size, with large droplets typically referring to those above 5-10 µm in

diameter, and small droplets or aerosols referring to those below 5-10 µm diameter. Forceful

respiratory actions such as coughing and sneezing can produce a burst of droplets that range in

size and could include both large droplets and aerosols that can present an exposure risk in close

proximity of an infected person. Evidence from animal studies has shown that transmission due to

close contact is likely to be more efficient than indirect transmission over longer distances.23-25 This

may be due to large droplets only travelling a limited distance before falling to the ground and the

concentration of aerosols released due to coughs, sneezes, or other respiratory action being higher

in close proximity to the emitter.26,27

The majority of respiratory emissions produced by less forceful respiratory activities such as

breathing, speaking, singing, shouting, or laughing produce smaller droplets or aerosols < 5 µm.28

Aerosols can remain suspended in air for a longer duration and be transported over larger distances

by ambient air currents.29-31 Under experimental conditions, SARS-CoV-2 has been found to remain

viable when airborne over short distances for several hours.32,33 Viable virus has also been isolated

from air samples at distances greater than 2 m from a COVID-19 patient, indicating that

transmission may be possible over longer distances.34 Increasingly, exposure to aerosols released

by an infected person is considered to be an important route of transmission, with some experts

calling for greater awareness of airborne precautions for some activities and in some

settings.6,27,29,35-38 This includes indoor environments where there is a high density of people and a

long duration of contact.5,39,40

Contact transmission

Contact with contaminated surfaces (fomites) followed by touching of the eyes, mouth, or nose is

another potential mode of SARS-CoV-2 transmission, although the relative importance of fomite

transmission is not fully understood.

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Pre-symptomatic and asymptomatic transmission

Understanding the dominant transmission pathways for SARS-CoV-2 has been complicated by the

occurrence of pre-symptomatic transmission (during the incubation phase of an infected person)

and asymptomatic transmission (transmission via an infected person who never displays

symptoms).41 The precise incidence of pre-symptomatic and asymptomatic transmission is

unknown, but it may be significant.41-43 Pre-symptomatic transmission may occur two to three days

before symptom onset, peaking before appearance of symptoms.44,45 Asymptomatic persons have

been found to transmit the virus at a similar rate and duration to those displaying symptoms.17,46

In the absence of symptoms such as sneezing and coughing, transmission routes other than via

large respiratory droplets are likely more significant for pre-symptomatic and asymptomatic

transmission.29

Infectious dose

The dose of SARS-CoV-2 required to cause an infection is still unknown. Initial evidence from animal

studies suggests that the minimum infectious dose varies by species but may be slightly higher than

SARS-CoV-1 and lower than Middle East Respiratory Syndrome (MERS), e.g., approximately a few

hundred viral particles.23-25,47-49 Animal studies have also indicated that infectious dose and

subsequent distribution of the virus in the host may vary by the route of infection.43,50

The quantity of virus contained in droplets and aerosols expelled by an infected person will vary by

the viral load in various parts of the respiratory tract and the stage of the disease. Viral load has

been found to be highest in the early stages of the disease and to be higher in sputum than in the

throat.51 Median viral loads have been found to be between 104 and 106 copies per mL of

respiratory fluid with an average emitter releasing about 106 copies per ml, but levels up to 1011

copies per mL have been detected in some cases.51-54 Infected super-emitters who release a greater

number of respiratory droplets could present a greater risk for transmitting the virus to others,

particularly if they also carry a high viral load. Environmental conditions such as relative humidity

and temperature can affect the movement of particles carrying the virus, virus survival, and

susceptibility of exposed persons to infection.

Understanding the transmission risks associated with

performing arts activities

Activities in the performing arts sector range from training and instruction in music, dance and

acting, rehearsals and practice sessions, live performances, and interaction with event organizers,

production and venue staff and audiences. The number and age of performers, the type and

intensity of performance, the level of interaction between performers, dancers or actors, the size

of the audience and the characteristics of the venue can vary widely. Each of these variables will

influence transmission via the various pathways discussed above, with settings and activities that

give rise to increased close contact, increased exposure to respiratory droplets and aerosols and

increased contact with contaminated surfaces, leading to increased risk of transmission. This

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includes settings where groups gather (rehearsals, performances, and audiences) and activities

that increase the release of respiratory droplets and aerosols due to vocalization during singing,

acting, playing of instruments, and vigorous physical activity such as dance.

Gathering in groups: Rehearsals, performances, and audiences

The vast majority of COVID-19 outbreaks have been linked to interactions in indoor environments,

particularly large group gatherings with close interactions over long durations.39,55,56 Activities that

involve rehearsing or performing in groups can result in multiple close interactions in rehearsal

venues, onstage, backstage, before and after rehearsals and performances, and during breaks.

Risks of transmission are increased during various activities:

• Group or partnered dance or performance segments, the sharing of dressing rooms, sheet

music, stands, or microphones or other similar activities make physical distancing difficult

to maintain and increases the risk of transmission via respiratory droplets and short-range

aerosols.

• Gathering in large numbers for long durations, in enclosed spaces with limited ventilation,

such as dressing rooms, orchestra pits, and small rehearsal rooms increases the risk of

accumulation of respiratory aerosols that do not drop to the ground or disperse with

ventilation.

• Sharing of surfaces and objects such as music stands, chairs, books, microphones,

instruments, props, hair and makeup supplies, food, dishes, cutlery, or drink dispensers

increases the risks of fomite transmission.

Risks due to close contact may be present for audiences seated or standing close together.

Audiences may also interact before and after the event, during intermissions, in refreshment

queues, washrooms, or while entering and exiting the venue where there is potential for close

contact and fomite transmission, due to contact with shared surfaces.

Singing and acting

Vocalization presents a risk of transmission via the production of respiratory droplets and aerosols

during speaking and singing. Loud speech and singing, while less forceful than coughing or

sneezing, can result in bursts of air releasing respiratory particles large enough to transport viruses,

including some small enough to be transported on air currents and inhaled deep into the

respiratory tract.35,57,58 Respiratory particles released by vocalization are generated by a

combination of mechanisms in the bronchioles, larynx, and oral cavity.28,59,60 The quantity and the

size of particles produced during vocalization enhances the risk of transmission compared to less

intense respiratory activities.

Release of respiratory droplets and aerosols due to vocalization: Quantity

Vocalization, whether speaking or singing, even at low volumes, produces a higher concentration

of aerosols than breathing, releasing hundreds to thousands of particles per second.28,59,61-64

Vocalization produces fewer aerosols per event than coughing or sneezing, but the total produced

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over time may be greater.65 Studies that have compared the quantity of aerosols produced by

singing and speaking at the same volume have reported contrary findings.28,62,64 These studies, and

others, do agree that the quantity of aerosols released increases with loudness, potentially due to

the greater inhalation and exhalation required for louder vocalization.28,59,62,64 The type of

phonation and articulation of different vowel and consonant sound can also affect the quantity of

particles released, with more exaggerated dictation potentially releasing more respiratory

particles.64-66

Studies have shown that some people emit a much larger quantity of particles than others. These

“super-emitters” have been found to release up to an order of magnitude more particles compared

to normal emitters.59,67 Asadi et al. (2020) estimated that a ten-minute conversation with an

asymptomatic super-emitter at normal volume could release up to 6000 aerosol particles.67

Multiple persons singing or speaking at once can release a greater source load of respiratory

particles compared to solo singing, acting, or loud speech. This may be important where more than

one infected person is present in a group.

Release of respiratory droplets and aerosols due to vocalization: Size

The majority of particles produced by vocalization, whether singing, shouting, cheering, or loud

speaking are aerosols less than 5 µm in diameter, and most may be less than 1 µm in

diameter.28,68,69 Aerosols are more likely to remain suspended than large droplets that quickly settle

to the ground due to the forces of gravity, although temperature, relative humidity, ventilation,

and ambient air currents will influence settling or dispersion.30 One study found that aerosols of

around 5 µm in diameter can take up to nine minutes to settle to the ground.69 They can be large

enough to carry infectious virus and a modelling study estimated that one minute of loud speaking

by an infected individual could produce up to 1000 virion containing particles.38

Playing musical instruments

The transmission risks associated with playing of musical instruments varies by the type of

instrument. Playing of strings, keys or percussion typically does not present added risks due to

respiratory droplets and aerosols but may present risks due to fomite transmission from shared

instruments. Instrumentalist that play more energetically could be inhaling and exhaling more

forcefully, which may increase the quantity of aerosols exhaled to the surrounding air.

Playing of brass and woodwinds may increase the release of respiratory particles by blowing air,

sometimes forcefully, through a mouthpiece. Respiratory particles may exit through the

instrument bell or keys, or across the surface for instruments such as the flute. Studies have

visualized both the air disturbance and the release of respiratory particles from various

instruments. Few studies have quantified the release of respiratory particles from brass and

woodwind instruments. A study of blowing through a vuvuzela found that more particles were

released, and at a higher velocity, than for loud shouting, with particles ranging in size from 0.5-5

µm.68 More recent studies of aerosol releases from instruments are emerging in the literature,

some of which are awaiting peer review.

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• A study at the University of Denmark measured aerosols released from brass and

woodwind instruments at distances of 0.5 to 4 m.70 The total mass of particles below 10

µm was similar to background levels for brass instruments (tuba, trombone, trumpet,

horn), and slightly higher for fagot, oboe, and flute; however, all instruments were

significantly lower than coughing at a distance of 0.5 m

• At Colorado State University, Volkens et al. (2020) found that trumpet, saxophone and

bassoon released more small aerosols than French horn, oboe and voice. Flute and piccolo

released the least.71

• At University of Minnesota, He et al. (2020) found that released aerosol concentrations

decreased with tube length, and mouthpiece design influenced aerosol concentration for

woodwinds.72 Tuba, bassoon, piccolo, flute, bass clarinet, French horn, and clarinet were

found to produce lower or similar levels of aerosols compared to normal breathing and

speaking. Trumpet, oboe, and bass trombone generated more aerosols than speaking.

Playing style for individual musicians influenced aerosol concentration.

An added transmission risk for brass instruments is the breath condensate that must be regularly

drained from the instrument. This concentrated fluid could potentially represent a risk of droplet,

aerosol, or fomite transmission if not carefully collected and disposed.73 Woodwind instruments

with reeds can also present another route of transmission if there is the sharing or touching of

other musicians reeds.74

Dance

There has been limited study of transmission risks specific to dance activities, with the risks

associated with gathering in groups of key importance. Table 1 lists clusters and outbreaks

associated with fitness classes, ballet companies, and ballroom/social dance instruction. The details

of outbreak investigations are lacking but there may have been several contributing factors such

as close personal contact with others, particularly for partnered dance, and enclosed and poorly

ventilated indoor spaces.

The importance of vigorous physical activity during dance to the risk of SARS-CoV-2 transmission is

not fully understood but physical activity can affect the quantity of air inhaled and exhaled and the

air flow velocity.75 Activities that result in deeper and faster inhalation and exhalation could

increase the quantity of respiratory particles released and the distance they travel. If breathing

zones of participants overlap, risk of inhaling particles released by others increases. A study of

infection risks of influenza and tuberculosis during physical exercise in gyms found that infection

risks increased with higher occupancy and poor ventilation.75 There are relatively few studies

examining transmission of SARS-CoV-2 during vigorous physical activity, with most of these linked

to fitness centres and classes.10,11,76 There many be similarities to dance in the types of fast

movements and physical exertion that occurs. A study of five cases linked to a squash court in

Slovenia found that the index case was a source of infection for his partner and other players using

the same court after him, despite never having physical contact. Droplets and aerosols released by

the index case during the squash match may have remained suspended due to poor ventilation

and turbulent air flow or became resuspended due to disruption of droplets that had settled on

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the floor. There is also potential that fomite transmission from touching of common surfaces within

the court or changing rooms could have been a contributing factor.77

Risk modifiers in the performing arts

Transmission of COVID-19 is complex, and there are no single measures, other than self isolation

from others, that can eliminate risk of infection entirely. In any setting, using multiple layers of

protection can reduce risks of exposure significantly. The considerations for reducing transmission

risks listed below are compiled from a wide range of Canadian public health and worldwide

performing arts sector guidance and literature.73,78-94 These do not supersede provincial health

orders and local public health and occupational safety requirements. The Public Health Agency of

Canada provides links to Provincial and Territorial resources for COVID-19 here. For most

performing arts activities, the standard suite of precautions for reducing risks of transmission

indoors apply, along with guidance specific to performing arts activities and venues.

Personal behaviours

Personal behaviours can affect the level of risk to an individual or others around them. Those who

are immunocompromised or vulnerable to infection should consider staying home. Persons who

are sick or have tested positive for COVID-19 or may have been exposed to known cases of COVID-

19 should also self-isolate according to local public health advice. In the outbreaks in choirs in

Washington State and Amsterdam, participants with symptoms attended the rehearsal(s) that

resulted in transmission of SARS-CoV-2 to others. Communication with groups prior to rehearsals

and events can include screening for symptomatic or highly susceptible persons, who should not

attend.

The potential for transmission via pre-symptomatic and asymptomatic persons requires additional

measures to reduce risks of transmission. Some groups may consider forming performance or

rehearsal cohorts to limit the number of interactions within a larger company. Limiting the number

of social contacts outside of a performance company or cohort can reduce the potential for

members of the group to be exposed to infection from the wider community. Members of a group

or company will rely on others practising safe personal behaviours outside of the group, such as

physical distancing and mask wearing when in public and practising good hand hygiene.

Distancing measures

Maintaining physical distancing of at least 2 m is an important control measure for reducing

transmission via large respiratory droplets and short-range transmission of aerosols. Physical

distancing should be maintained between members or choirs, bands, dance companies, and

theatre groups wherever possible, particularly during rehearsals and instruction. Face-to-face

arrangement of performers should be avoided. Distancing should also be maintained between

performers and the audience, technical staff, and venue staff, with mingling or socializing before

or after rehearsals or performances discouraged. For performers playing wind instruments,

distancing may need to be greater than 2 m to account for the length of the instrument.

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Maintaining physical distancing may be more challenging in dance and theatre settings. Creative

adaptations to performances may be needed to reduce the potential for close encounters and to

avoid performers crossing through the breathing space of others. Assigning performers with

designated areas on a stage/floor can prevent overlap of performance areas. Partnered dance or

performance segments that require close contact could be adapted or limited to persons from the

same household where possible.

The use of partitions is not practical in all settings but may be considered where it is safe to do so,

either between stationary performers, or between performers and audiences. Maintaining

distancing should not be limited to performance areas, and consideration for reducing close

encounters in dressing rooms, washrooms, and backstage should be made such as floor markings,

one-way flow of traffic, and occupancy limits for small spaces.

Box 1: Innovations for Keeping Audiences Distant:

The use of bigger venues makes separating audiences easier by allowing multiple entrances and exits and distancing between groups. Live concerts at a Cologne Germany arena have proceeded with reduced capacity of 1000 to 2400 by implementing distancing and hygiene

rules and using plexiglass cubes to separate the audience into small groups of up to eight people. In Leipzig Germany, an experimental indoor live concert provided 1500 volunteers with fluorescent hand gel and electronic contact trackers to trace the contact rates and distances for three scenarios. The outcomes of the study will inform how various measures can reduce transmission risks.

Image credit: GettyImages

Reducing density and duration

Crowding makes it difficult to maintain physical distancing and allows for rapid accumulation of

exhaled aerosols, which can be transported on air currents. There may be no safe physical distance

to reduce risks to a negligible level if one or more infected persons, or a super-emitter with a high

viral load, is present in an enclosed space.54 Reducing the density of participants and the duration

they spend in a space can reduce the potential exposure dose. Large groups should avoid activities

in closed, unventilated rooms even with distancing measures in place. Maximum occupancy limits

or moving activities to larger spaces can reduce the concentration of exhaled air in a space.

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Duration limits vary by jurisdiction, ranging from 15 minutes to no specified limit. Based on current

standards of ventilation for many indoor environments, one study estimated that occupancy of 30

minutes is recommended for an infection risk level below 10% for high-emission activities.6 The 30-

minute limit followed by a break outside of the room, or moving to an alternative space, to allow

the room air to clear is a commonly recommended duration for activities such as choir singing.

Masks

The use of face coverings whenever possible while around others can block emissions of droplets

and reduce the spread of aerosols, but masks do not remove transmission risks entirely.71,95-97 To

reduce reliance on masks while performing, some theatre companies are adapting performances

to reduced speaking or using voice-over narration as an alternative.98 Where masks are used, the

most effective are those that fit well, without gaps around the nose bridge, chin, and sides, and

those made of materials that effectively block the movement of both droplets and aerosols. Many

homemade masks and adaptations of traditional masks have not been assessed for their

effectiveness. Masks such as singers’ masks, adapted for use during rehearsal and performance,

have not been widely assessed (Box 2).

Box 2: Innovation in Masking for the Performing Arts

Several versions of performers’ or singers’ masks (pictured) have been designed that allow for greater articulation and mouth movement. Similarly singers face shields adapt the concept of conventional face shields by adding a cloth covering around the edges of the shield to prevent the outward movement of droplets and aerosol. The effectiveness of these for reducing transmission risks has not been assessed in the literature.

Image credit: Broadway Relief Project

Standard masks have also been adapted for playing of some wind instruments by cutting a straight

opening in the centre of the mask for the mouthpiece to allow the instrument to be played while

the performer wears a mask. These masks should be replaced with unaltered masks when not

performing. Masks, or bell covers, for instruments are also recommended to prevent the release

of aerosols during playing. An alternative for flutes is a pop screen in front of the mouthpiece that

can reduce forward projection of droplets and aerosols.

Ventilation

Ventilation can affect the distribution and persistence of potentially infectious aerosols in a room.

One study found that in well-ventilated rooms, the number of droplets produced by simulated

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coughing (average 5 µm in diameter) halved within 30 seconds, compared to five minutes in the

unventilated rooms.69 Stadnytskyi et al. (2020) similarly found that airborne particles released by

vocalization in a stagnant air environment were detected 8 to 14 minutes after speaking.38

Moving activities outside wherever possible is recommended. Outside air can help to dilute

infectious particles to low levels and air flow can help to disperse particles (Box 3).

Box 3: Moving Performances Outside

Image credit: 604now.com

Until audiences can safely attend performances in sufficient numbers to be financially sustainable, some groups may not return to indoor venues. Innovations for outdoor venues have been observed in many countries the form of drive-in concerts (left) and the use of hundreds of socially distanced pods keeping small groups distanced from each other.

When inside, moving activities to larger rooms with good air exchange is recommended.99 Larger

room sizes allow for greater dilution of respiratory particles, but without proper ventilation,

particles can accumulate and disperse within the room over time. Opening windows or exterior

doors can be effective where mechanical ventilation systems are not available, but how air is

flowing within a space should also be considered. Portable fans should be used with caution to

ensure they are not simply dispersing contaminated air around a room. Mechanical ventilation, or

well-planned natural ventilation can help remove particles with upward air flow exhausted to the

outside, and can dilute indoor air with clean outdoor air.73

While recirculating systems are discouraged, where unavoidable, control measures to improve

conditions such as increased percentage of outside air in ventilation, high-quality filters (e.g.,

MERV-12), or integrated disinfection systems (e.g., UV germicidal irradiation, either in ducts or in

an upper room configuration) can be used to minimize recirculating virus.100,101 Small and poorly

ventilated areas may require breaks or alternative between two rooms to reduce the build-up of

aerosols and allow room air to clear between uses. The use of portable air cleaners could be

considered where other ventilation strategies are not possible.100 Using portable air cleaners with

high-efficiency particulate air (HEPA) filters can remove virus-laden aerosols from the air.102 The

effectiveness is influenced by the clean air delivery rate (CADR) of the air purifier (e.g., the volume

of air that can be processed over a given time) as well as proper operation and maintenance of the

system, such as changing and safe handling of filters at specified intervals.

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Cleaning and disinfection to reduce fomite transmission

Control measures for fomite transmission include good hand hygiene practices and routine

cleaning and disinfection of surfaces, as well as avoiding sharing of equipment, props, musical

stands, instruments, costumes, microphones, and food and drinks. Where use of shared

microphones is unavoidable, the use of disposable foam screens could be considered, which should

be changed between performers followed by disinfection of surfaces where appropriate.

Performers are also encouraged to keep their costumes apart from others and wash and clean

them after each use or performance. Similarly, performers should consider doing preparation

offsite, such as hair and makeup. Precautions should be taken for hair and makeup done onsite,

such as avoiding the use of communal brushes and makeup supplies.

Although sharing of musical instruments is discouraged, cleaning and disinfection of instrument

surfaces and mouthpieces should still be done routinely to reduce the possibility of fomite

transmission. Guidance on cleaning and disinfection procedures and materials should be reviewed

to ensure a thorough process is followed, while avoiding damage to the instrument.103 For brass

instrument players that empty condensate through spit valves, care should be taken to safely

collect and dispose of condensate into a cloth or closed container followed by handwashing and

hand sanitizing to prevent cross contamination of the instrument surface, chairs, music stands, or

the floor.

Considerations for audiences

While jurisdictions will set the occupancy limits and detailed criteria specific to venues for allowing

audiences to return to live performances, the principles of encouraging distancing, mask wearing,

good hand hygiene, and respiratory etiquette should be applied. Communication with audiences

prior to events can allow organizers to clearly set out COVID-19 safety protocols, to provide

screening questionnaires regarding symptoms and exposures, request ill persons to stay at home,

and to gather information for contact tracing following the event if needed. Some guidance

recommends discouraging audiences from singing, cheering, dancing, and laughing. This can be a

difficult request, but providing audiences with alternative ways to join in such as humming,

clapping, or providing handheld noisemakers, can allow audiences to engage and to express their

appreciation for the performance without vocalizing it.

Conclusions

Several factors may have contributed to COVID-19 clusters and outbreaks in performing arts

settings, which include characteristics of the settings (indoors, crowded, poor ventilation), the

activity (close interactions, loud vocalization, heavy breathing or exertion) and the prevalence of

community transmission. Current evidence suggests that activities such as loud vocalization

(speaking, singing, cheering, laughing) and physical exertion increase the quantity of small

respiratory particles that can accumulate and remain suspended in air and could contribute to

transmission risks. While the local epidemiological situation is the key driver of when and how

activities will resume or scale up in various jurisdictions, there are precautions and control

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National Collaborating Centre for Environmental Health 15

measures that can be used to create several layers of protection for reducing transmission via

respiratory droplets and aerosols and via fomites.

One of the limitations of this review is the lack of published details of epidemiological investigations

of clusters and outbreaks. Further research is needed to better understand the concentration,

infectiousness, and transport distance of SARS-CoV-2 in aerosols, and the dose-response

relationship for SARS-CoV-2. Research and examples of what has worked or not worked in other

jurisdictions will also be valuable in guiding and informing implementation of measures to reduce

COVID-19 risk for performers, audiences, and production and support staff.

Acknowledgements

This document benefited from the contributions of Michele Wiens (NCCEH) and Lydia Ma (NCCEH).

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91. Kähler CJ, Hain R. Singing in choirs and making music with wind instruments ‒ Is that safe during the SARS-CoV-2 pandemic? Germany: Universität der Bundeswehr München; 2020. Available from: https://www.unibw.de/lrt7-en/making_music_during_the_sars-cov-2_pandemic.pdf. 92. International Association for Dance Medicine & Science. Resources for COVID-19. 2020; Available from: https://www.iadms.org/page/coronavirus. 93. American Choral Directors Association. COVID-19 response committee report. Oklahoma City, OK: American Choral Directors Association; 2020 Jun 15. Available from: https://acda.org/wp-content/uploads/2020/06/ACDA-COVID-19-Committee-Report.pdf. 94. UK Department for Business Energy & Industrial Strategy, UK Department for Digital Culture Media & Sport. Working safely during coronavirus (COVID-19): performing arts. London, UK: UK Government; 2020. Last updated Sept 11. Available from: https://www.gov.uk/guidance/working-safely-during-coronavirus-covid-19/updates. 95. Leung NHL, Chu DKW, Shiu EYC, Chan K-H, McDevitt JJ, Hau BJP, et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med. 2020 Apr 3. Available from: https://doi.org/10.1038/s41591-020-0843-2. 96. O'Keeffe J. Masking during the COVID-19 pandemic. Vancouver, BC: National Collaborating Centre for Environmental Health; 2020 Apr 17. Available from: https://ncceh.ca/documents/guide/masking-during-covid-19-pandemic. 97. International Coalition of Performing Arts. International Coalition of Performing Arts Aerosol Study Round 2 Indianapolis, IN: National Federation of State High School Associations; 2020 Aug. Available from: https://www.nfhs.org/media/4030003/aerosol-study-prelim-results-round-2-final.pdf. 98. Cappelle L. In France, live theater calls for masked actors and creative solutions. New York Times. 2020. Available from: https://www.nytimes.com/2020/08/20/theater/france-theater-coronavirus.html. 99. Scheuch G. Breathing is enough: for the spread of influenza virus and SARS-CoV-2 by breathing only. J Aerosol Med Pulmon Drug Del. 2020. Available from: https://www.liebertpub.com/doi/abs/10.1089/jamp.2020.1616. 100. Evans M. Avoiding COVID-19: aerosol guidelines. medRxiv. 2020. Available from: http://medrxiv.org/lookup/doi/10.1101/2020.05.21.20108894. 101. Morawska L, Tang JW, Bahnfleth W, Bluyssen PM, Boerstra A, Buonanno G, et al. How can airborne transmission of COVID-19 indoors be minimised? Environ Int. 2020;142:105832. Available from: https://doi.org/10.1016/j.envint.2020.105832. 102. Zhao B, Liu Y, Chen C. Air purifiers: A supplementary measure to remove airborne SARS-CoV-2. Build Environ. 2020 2020/06/15/;177:106918. Available from: https://doi.org/10.1016/j.buildenv.2020.106918. 103. National Federation of State High School Associations. COVID-19 Instrument Cleaning Guidelines. 2020 [updated Apr 24]; Available from: https://www.nfhs.org/articles/covid-19-instrument-cleaning-guidelines/.

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Appendix 1: Rapid review method and search and terms

A rapid literature search was performed by the NCCEH information specialist using Ebscohost

databases (includes Medline, Cinahl, Academic Search Complete, ERIC, etc.), and Google Scholar,

with no date or jurisdictional limit, for English language documents. Further examination of

bibliographies of key articles were scanned to retrieve more extensive information, and key authors

in the subject area were searched to identify additional relevant citations. Forward chaining of key

papers added to the search results and news reports identifying localized outbreaks associated

with performing arts were scanned for details of outbreak investigations.

Search Terms: Variants and Boolean operator combinations, e.g.,: (choir OR choral OR chorale OR singers OR chorister OR band OR opera OR ensemble OR “musical group” OR “music group” OR accompanist OR musician OR instrumentalist) AND (singing OR sing OR vocal OR vocalization OR rehearsal OR audition OR voice OR “forceful exhalation” OR exhale OR “lung capacity” OR speaking OR “speaking loudly” OR eject OR “forced Expiratory Volume” OR yelling OR screaming OR sharing) (aerosol OR aerosolization OR aerosolization OR droplet OR crowding OR ventilation OR expel) (predisposition OR vulnerability OR laryngeal OR illness) AND (transmission OR transmit OR infect OR infectious OR infectiousness OR infectivity OR illness OR virus OR viral OR influenza OR airborne OR expelled OR propel OR “Upper respiratory tract infections” OR respiratory OR sick OR sickness OR epidemiology OR outbreak OR “case report”) (“seating arrangement” OR practice OR “wind instrument” OR woodwind OR brass OR oboe OR flute OR clarinet OR saxophone OR bassoon OR recorder OR trumpet OR trombone OR euphonium OR tuba) (“social connection” OR “connectedness” OR bonding OR socialization) (coronavirus OR ncov OR "novel cov” OR COVID-19 OR SARSCOV-2 OR Sars-Cov-19 OR SarsCov-19 OR SARSCOV2019 OR "severe acute respiratory syndrome cov 2" OR "2019 ncov” OR "2019ncov”) (dance OR ballet OR play OR theatre OR theater OR hall OR audience OR workout OR karaoke) (class OR classes OR studio OR show OR performance OR audition OR practice OR practise OR rehearse OR rehearsal OR “performing arts”) (“live music” OR orchestra OR opera OR operetta OR festival OR “stage show” OR musical OR venue OR “art group” OR concert) (dancer OR performer OR cast OR crew OR ballerina OR actor OR musician) (Mariinsky OR Petersburg OR Boshoi OR Moscow) (fitness OR exercise OR zumba OR aerobics OR workout OR disco OR jazzercise OR danceworks) ("fitness center" OR "fitness centre" OR "fitness facility" OR "fitness facilities" OR OR gymnasium OR gym) ("dance event" OR nightclub OR "night club" OR nightlife OR "night life" OR lounge OR hookah OR bar OR karaoke OR "after hours" OR partiers OR bar OR pub OR legion OR tavern OR festival ) AND (cardiovascular OR volume OR lung) (aerosol OR aerosolization OR aerosolization OR droplet OR crowding OR ventilation OR expel) (predisposition OR vulnerability OR laryngeal OR illness) AND

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National Collaborating Centre for Environmental Health 22

(transmission OR transmit OR infect OR infectious OR infectiousness OR infectivity OR illness OR virus OR viral OR influenza OR airborne OR expelled OR propel OR “Upper respiratory tract infections” OR respiratory OR sick OR sickness OR epidemiology OR outbreak OR case OR report OR study) (coronavirus OR ncov OR "novel cov” OR COVID-19 OR SARSCOV-2 OR Sars-Cov-19 OR SarsCov-19 OR SARSCOV2019 OR "severe acute respiratory syndrome cov 2" OR "2019 ncov” OR "2019ncov”)

ISBN: 978-1-988234-44-1

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This document can be cited as: O’Keeffe, J. COVID-19 Risks and precautions for the performing arts.

Vancouver, BC: National Collaborating Centre for Environmental Health. 2020 Sep. Permission is granted to reproduce this document in whole, but not in part. Production of this document

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